Dinitro-1,3-p

ABSTRACT

2,4-Dinitro-1,3-phenylenediamine compounds having a lower alkyl or cyano substituent at the 6-position of the ring are useful as herbicides.

United States Patent [191 Hunter et al.

1 *Oct. 7, 1975 1 DINlTRO-l,3-P

[75] Inventors: Don L. Hunter, Anaheim; William G. Woods, Fullerton; James D. Stone, Whittier, all of Calif.; Cecil W. LeFevre, Franklin, ldaho [73] Assignee: United States Borax & Chemical Corporation, Los Angeles, Calif.

[ Notice: The portion of the term of this patent subsequent to Nov. 2, 1988, has been disclaimed.

[22] Filed: Nov. 2, 1970 [21] App]. No.: 86,386

[52] US. Cl. 71/105; 71/83; 71/92; 71/93; 71/121; 260/465 E; 260/577 Primary ExaminerJames 0. Thomas, Jr. Attorney, Agent, or FirmJames R. Thornton [5 7 ABSTRACT 2,4-Dinitro-1,3-phenylenediamine compounds having a lower alkyl or cyano substituent at the 6-position of the ring are useful as herbicides.

8 Claims, No Drawings 'DINIT'RO-L3-P This invention relates to -2,4-dinitro-l,3-

phenylenediaminecompounds and their use as herbicides. There is provided by this invention a class of 2,4- dinitro-N-substituted-l ,3-phenylencdiamine compounds having an alkyl or cyano substituent in the 6- position of the aromaticring. The compounds have outstanding herbicidal activity.

The herbicidal compounds of this invention can be defined by the formula V wherein Z is lower alkyl or cyano, each R is selected from hydrogen, alkyl and alkenyl and R is selected from alkyl and alkenyl.

For convenience in naming the compounds, the amino nitrogen adjacent to the alkyl or cyano group is referred to as N and the aminonitrogen between the nitro groups on the ring is referred to as N -Thus, the nitro substituents are in the 2 and 4 position of the aromatic ring and the alkyl or cyano group is in the 6 position ofthe aromatic ring. lt will be noted from the above definition that the N amino nitrogen must' have at least one hydrocarbon substituent thereon, thereby excluding the compounds having an unsubstituted amino (NH group at this position.

Typical examples of hydrocarbon groups represented by R and R as defined above are the lower alkyl and lower alkenyl groups having up to about 6' carbon atoms, including the cyclic analogues thereof as well as X Z N02 R1\ NH the halo and lower alkoxy substituted derivatives thereof. Representative groups are methyl, ethyl, n-

propyl, isopropyl, n-butyl, sec-butyl, n-pentyl, secpentyl, n-hexyl, allyl, Z-butenyl, methallyl, 2- methoxyethyl, 3-e thoxypropyl,- 2-chloroallyl, 2-

2 N-ethyl N,N -diallyl-2,4-dihitro}6-methyl-l ,3 phenylenediamine s N -methyl-Nsec-butyl-2,4-dinitro-6-cyano-l ,3- phenylenediamine N -ethyl-N"-sec-butyl-2,4-dinitro-6-methyll ,3- phenylenediamine N -methyl-N ,N -di-n-propyl-2,4-dinitro-6-isopropyl 1,3-phenylenediamine N ,N -cli-n-propyl-2,4-dinitro-6-methyl-l ,3-

phenylenediamine N -methyl-N ,N -diethyl-2,4-dinitro-6-cyano-1,3-

phenylenediamine N ,N -diethyl-2,4-dinitro-6-ethyl-l ,3-

phenylenediamine N 3-pentyl )-2,4-dinitro-6-cyano-l ,3

phenylenediamine N -methyl-N l-methyl-2-methoxyethyl )-2,4-dinitro- 6 -methyl-1,3-phenylenediamine N -methyl-N -cyclopropy1-2,4-dinitro-6-ethyl-l ,3-

phenylenediamine N-sec-pentyl-N ,N -dimethyl-2,4-dinitro-6-methyl l ,3-phenylenediamine N -(3-chloro-n-propyl)-2,4-dinitro-6-methyl-1,3-

phenylenediamine N -(4-heptyl )-2,4- dinitro-6-methyl- 1 ,3-

phenylenediamine N -(4-chloro-2 -butenyl)-2,4-dinitro-6-methyl-1 ,3-

phenylenediamine N -sec-butyl-2,4-dinitro-6-methyll ,3-

phenylenediamine The compounds of this invention are either crystalline solids or high boiling liquids. Generallythey are only slightly soluble in water and are moderately soluble in the usual organic solvents such as ethanol, ace-1 tone, ether and benzene. The compounds are readily prepared by reaction of one ortwo amines or ammonia with a 2,4-dihalo-3,S-dinitroalkylbenzene or -benzonitrile according to the following equation:

in which X is a reactive halogen such as bromo or chloro and'Z, R and R have the significance previously assigned. When y R 'NH and NH l/ R are .the same, thatis when the 'substituted N amino group is the same as the substituted N amino group in the resultant product, the reaction can take place in one stepusing at-least tvvomoles of the'amine fofr each mole of 2,4-dihalo3,S-dinitrobenieh'ecompound.The

hydrogen halide can be neutralized by excess amine or a tertiary amine. When is different from drohalide is insoluble and can be removed by filtration.

1n the second step about two moles of the amine forming the N group is reacted with the monoaminosubstituted compound to form the unsymmetrically substituted 1,3-phenylenediamine compound. The second reaction is advantageously carried out in a sealed reaction vessel, such as a sealed tube or an autoclave, or at atmospheric pressure in the presence of a solvent, such as an alcohol or high boiling ether in which the amine is highly soluble. In the case of higher boiling amines it is not necessary to use a sealed reaction vessel for the-reaction but it is sufficient merely to carry it out in the presence of a suitable solvent.

A reaction temperature in the range of from about 20 to about 120C. preferably is employed to give good yields of the desired product and a satisfactory rate of reaction, both in the case of using a sealed reaction vessel and when the reactants are brought together at atmospheric pressure. Hydrogen halide is formed as a by-product and, in the presence of excess amine, is converted to the amine hydrohalide which can be readily removed by washing with water or by filtration after dissolution of the product in a suitable solvent. The desired products can be purified by well known procedures such as by recrystallization.

The following examples describe preparation of rap resentative compounds of this invention but it is to be understood that the invention is not to be limited to the specific examples given.

EXAMPLE I N-(3-penty1)-3-chloro-2,6-dinitro-4-methylaniline 3-Pentylamine (10.4 g.; 0.1 194 mole) and 2,4- dichloro-3,S-dinitrotoluene (15.0 g.; 0.0597 mole) in ml. of dimethoxyethane were charged to a 50 ml. reaction tube. The tube was sealed and placed in an oven at 94C. for 22 hours. The tube was then opened and the contents were evaporated to dryness under reduced pressure to leave an orange residue. The residue was extracted with 200 ml. of boiling hexane for one hour. After cooling the mixture was filtered and the filter cake washed with hexane. The filtrate was evaporated to an orange oil which slowly crystallized. The residual oil was taken up in 60 ml. of refluxing EtOH and on cooling the product crystallized. The product was isolated by filtration and dried to give 9.18 g. of N-(3- pentyl)3-chloro-2,6-dinitro-4-methylaniline, m.p. 6162.5C. After recrystallization from 95% EtOH, the product melts at 6263.5C.

N -(3pentyl)-2,4 -dinitro-6-methyl-1 ,3-phenylenediamine A mixture of 5.00 g. (0.0165 mole) of N-(3-pentyl)- 3-chloro-2,6-dinitro-4-methylaniline and 30 ml. of dimethoxyethane was charged to a glass reaction tube. The tube was cooled, 5 ml. of anhydrous ammonia condensed into it, and the tube was then sealed. After heating for 5 hours at 94C., the tube was opened and the reaction mixture was stripped of volatile material. The residue was taken up in 250 ml. of hot cyclohexane, the solution filtered while hot, then stripped to give an orange residue which was crystallized from 95 percent ethanol to give 1.02 g. of the desired product as orange needles, m.p. 157160.5C. After recrystallization from 95 percent ethanol the product melts at EXAMPLE n N ,N -diethyl-2,4-dinitro-6-methyll ,3- phenylenediamine This compound was prepared in a similar manner by reaction of N,N-diethyl-3-chloro-2,6-dinitro-4- methylaniline with ammonia. The crystalline product melts at l08109C.

EXAMPLE lll N ,N -di-n-propyl-2,4-dinitro-6-methyl-l ,3- phenylenediamine This compound was prepared in a similar manner by reaction of N,N-di-n-propyl3-chloro-2,6dinitro-4- methylaniline with ammonia. The crystalline product melts at l26l27C.

EXAMPLE IV N -sec-butyl-2 ,4-dinitro-6-methyl- 1 ,3- phenylenediamine This compound was prepared in a similar manner by reaction of N-sec-butyl-3-chloro-2,6-dinitro-4- methylaniline with ammonia. The crystalline product melts at 15l.5152.5C.

EXAMPLE V N( 3-pentyl )-2,4-dinitro-6-ethyll ,3- phenylenediamine 2,4-Dichloroethylbenzene (prepared by Wolff- Kishner reduction of 2,4-dichloroacetophenone) was nitrated by reaction with a mixture of nitric and sulfuric acids. The resultant 2,4-dichloro-3,S-dinitroethylbenzene was aminated with 3-pentylamine and then ammonia according to the procedure of Example I to give N (3-pentyl)-2,4-dinitro-6-ethyl-1,3-phenylenediamine, m.p. 156.5157.5C.

EXAMPLE v1 N,N-diethyl-3-chloro-2,6-dinitro-4-cyanoaniline To a mixture of 4.65 g. (0.0177 mole) of 2,4- dichloro-3,S-dinitrobenzo'nitrile and 200 ml. of dimethoxyethane was added 2.59 g. (0.0354 mole) of diethylamine in 20 ml. of dimethoxyethane. The amine was added dropwise to the stirred solution at room temperature over a period of 3 hours. The reaction mixture was then stirred an additional 17 hours at room temperature. The reaction mixture was evaporated to dryness and the residue extracted with 200 ml. of diethyl ether. The ether solution was filtered and then evaporated to dryness to give 4.33 g. (82 percent) of N,N-diethyl-3- chloro-2,6-dinitro-4-cyanoaniline, identified by its nuclear magnetic resonance spectrum.

N ,N -diethyl-2,4-dinitro-6-cyanol ,3-

phenylenediamine A solution of 4.33 g. (0.0144 mole) of N,N-diethyl-3- chloro-2,6-dinitro-4-cyanoaniline, 6.40 g. (0.0288 mole) of a 7.66 percent solution of ammonia in absolute ethanol, and ml. of dimethoxyethane was sealed in a Pyrex reaction tube and allowed to stand at room temperature for 72 hours. The contents were distilled to dryness at reduced pressure and extracted with 100 ml. of boiling chloroform. The filtered chloroform extract was evaporated to dryness and the residual orange solid taken up in hot 95 percent ethanol. Upon cooling, the product crystallized and was isolated by filtration to give 1.51 g. (37.3 percent) or an orange, crystalline solid melting at l42l45C. Recrystallization from 95 percent ethanol gave the desired product, m.p. 145.5146.5C.

EXAMPLE VII N ,N -diethyl-2,4-dinitro-6-methyll ,3- phenylenediamine A glass reaction tube was charged with a solution of 5.0 g. (0.02 mole) of 2,4-dichloro-3,5-dinitrotoluene in 15 ml. of 1,2-dimethoxyethane. The tube was then chilled in a Dry Ice-acetone bath and 5.64 g. of 70 percent aqueous ethylamine (0.0876 mole) was added. The tube was then sealed, warmed gently and shaken to provide a homogeneous solution and then heated in an oven at 110C. for hours. The reaction mixture was removed from the tube and the solvent and volatiles removed by distillation under reduced pressure. Absolute ethanol was added to the solid residue and then stripped to removed the last traces of water. The dried residue was extracted with 200 ml. of refluxing diethyl ether for one hour and the cooled mixture filtered to removed insoluble amine hydrohalide. The ether filtrate was evaporated to dryness to give a solid orange crystalline product. Recrystallization from 95 percent ethanol gave 3.96 g. (74 percent) of product melting at 59.5-6l.5C.

EXAMPLE VIII N ,N -diisopropyl-2,4-dinitro-6-methyl-l,3- phenylenediamine This compound was prepared in a similar manner by reaction of 2,4-dich1oro-3,5-dinitrotoluene with isopropylamine to give the crystalline product melting at 9697C.

The 3,5-dinitro-2,4-dihalo-alkylbenzene and henzonitrile starting materials are prepared by known nitration reactions of the corresponding 2,4-

dihaloalkylbenzenes and benzonitriles. See also British Pat. No. 951,770.

The compounds of this invention are excellent herbicides and are especially useful as selective herbicides for controlling weeds in the presence of desirable crops, especially the control of grassy weeds, such as water grass and crabgrass, as well as pigweed.

The compounds can be applied as both a preemergence or a post-emergence treatment; that is they can be applied to soil in which the weeds will grow or they can be used to kill or suppress the growth of growing weeds or to kill or prevent the emergence of seedlings of undesirable plants. Thus, the compounds can be used to control the growth of weeds by applying a phytotoxic amount of one or more of the active compounds of this invention to the locus to be protected, that is, soil in which the weeds are growing or will grow or the foliage of the growing plants. Weeds as used herein is meant to include any plant growth which is undesirable.

Generally an application rate of from about 0.5 to about 25 pounds of one or more of the active compounds per acre is effective in controlling plant growth. Preferably an application rate of from about 1 to about 8 pounds per acre is employed. At such rates, undesirable weeds are killed or stunted with little or no injury to desirable crops.

The following examples illustrate the herbicidal activity of typical compounds of this invention.

EXAMPLE IX The compounds to be tested were evaluated as both a pre-emergence and post-emergence treatment. Greenhouse flats were planted to soybeans (SB), velvet leaf (VL), oats (O) and millet (M) and the flats sprayed on the same day as planting with an ethanoldioxane solution of the compound to be tested at a rate of 5 pounds per acre.

Another set of flats with the same plants was treated after the plants had emerged and were about one inch in height. These flats were also sprayed with an ethanol-dioxane solution of the compound to be tested at a rate of 5 pounds per acre. The flats were kept in the greenhouse and watered when needed. Twenty-one days after treatment the flats were examined and the plants rated for herbicidal activity on a 0 to 9 scale in which 0 no effect, 5 substantial injury with some kill, and 9 complete kill. The following results were obtained.

TABLE I COMPOUND ACTIVITY Pre Post SB VL M SB VL o M N ,N dicthyl-2,4-dinitrofi-rnethyld ,3phenylenediamine 1 4 2 9 3 7 o 6 N ,N -di-n-propyl-2,4- dinitro-(i-methyh l ,3- phenylencdiaminc l 2 l 9 3 6 5 6 N,N -diethyI-2,4-dinitro- 6methyl-l ,3phenylene diamine l 2 l 8 2 2 3 7 N ,N" diethyl-2,4dinitro- -cyano-l ,3-phenylenediamine l 4 4 9 2 4 2 4 N -(3-pentyl)-2,4-dinitr0- 6-methyl-l ,B-phcnylenediamine 2 4 5 9 3 4 l 5 N',N"',diis0propyl2,4- dinitro-o-methyl-l ,3- phenylenediamine O O 0 O l 2 O 2 N -sec-butyl-2,4-dinitr0' 6-rncthyl l ,3-phenylcnediaminc O 3 O 9 l 4 O 5 Since a relatively small amount of one or more of the pound may be suspended or dispersed can be used. A active 2,4-dinitro-1,3-phenylenediamines should be surfactant is also generally included to facilitate such uniformly distributed over the area to be treated, the dilution or dispersion in water. However, the surfactant compounds preferably are formulated with convenitself may comprise the carrier in such concentrates. tional herbicide carriers, either liquid or solid. Thus, The herbicidal compositions can include other benethe compounds can be impregnated on or admixed with ficial adjuvants, such as humectants, oils and contact a pulverulent solid carrier such as lime, talc, clays, Benagents s other herbicides such as the i m tonite, calcium chloride, vermiculite, calcium carbon fates, di m hlorate, chlorophenoxyacetic aC ate, and the like. Alt ati l th compounds can b substituted urac'ils and ureas, triazines, benzimidazoles, dissolved or suspended in a liquid carrier such as water, Cafbamates, m and haloalkafioic i can be kerosene, alcohols, diesel oil, xylene, benzene, glycols, lud in th f mulationketones, and the like. A surfactant preferably is in- Various changes and modifications of the invention eluded to aid in dispersion, emulsification and covera be m n to h x n h h v riations inage. The surfactant can be ioni or m -io i d may corporate the spirit of this invention, they are intended be liquid or a solid. The use of the term surfactant be included Within the Scope of the app Claims herein is intended to include such compounds com- W i im iSZ monly referred to as wetting agents, dispersing agents 40 l. The me hod for controlling weed growth which and emulsifying agents. Typical surfactants include the comp ises applying to the locus of said weeds :1 phytoalkylarylsulfonates, the fatty alcohol sulfates, sodium toxic amount of a compound of the formula salt of naphthalenesulfonic acid, alkylaryl polyether alcohols, long chain quaternary ammonium compounds, sodium salts of petroleum-derived alkylsulfonic acids, polyoxyethylene-sorbitan monolaurate, and the like. These dispersing and wetting agents are sold under numerous trademarks and may either be pure compounds, mixtures of compounds of the same general group, or they may be mixtures of compounds of different classes. Surfactants can also be included in compositions containing a solid inert carrier.

Concentrated compositions containing the active agent which can be subsequently diluted, as with water, m which Z 15 Cyano, each 1 Elected from group to the desired concentration for application to plants conslsm'lg of hydrogen, lower alkyl, and lower y i and soil are also provided. The advantages of such conand 2 15 Selected m the g p Consisting of lower centratcs are that they are prepared by the manufacalkyl and er ny Said lower alkyl and lower alturer in a form such that the user need only mix them kenyl g p having p. t0 about 6 Car on atoms with a locally available carrier, f bl water, 2. The method In accordance with claim 1 in which thereby keeping shipping costs to a minimum while 531d Compound 15 pp at a fate of about 1 0 8 providing a product which can be used with a minimum Pounds P acre of equipment and effort. Such concentrates may con- 3. The method in accordance with claim 1 in which tain from about 5 to about 99 percent by weight of one Said compound is y -2,4- in ro-6-cy no or more of the active 2,4-dinitro-l,3- -p enylenediamine phenylenediamines with a carrier or diluent, which may be a liquid or a solid. Liquid carriers which are miscible with the active agent or other liquids in which the com- 4. The method in accordance with claim 2 in which said weeds are grassy weeds.

5. The method in accordance with claim 1 in which an inert carrier and a surfactant, in which Z is cyano, each R 1 is selected from the group consisting of hydrogen, lower alkyl and lower alkenyl and R is selected from the group consisting of lower alkyl and lower alkenyl, said lower alkyl and lower alkenyl groups having up to about 6 carbon atoms.

and

Z NO

R N 1 02 R UNITED STATES PATENT AND TRADEMARK OFFICE QETlFlQATE 0F CCRECTTCN g PATENT NO. 1 3,910,783

DATED 1 October 7, 1975 INVENTOR( i D.L. Hunter, W.G. Woods, J.D. Stone, C.W. LeFevre It is certified that error appears in the above-identified patent and that said Letters Patent I o are hereby corrected as shown below:

On Title page and in Column 1 delete Dinitro-l,3-P

and add --Dinitro-l,3-Phenylenediamine Compounds-- In Column 9, lines 1 6 delete the following:

"an inert carrier and a surfactant, in which Z is cyano, each R is selected from the group consisting of hydrogen, lower alkyl and lower alkenyl and R2 is selected Q from the group consisting of lower alkyl and lower al- Kenyl, said lower alkyl and lower alkenyl groups having up to about 6 carbon atoms.

In Column 10, line 19 delete and add the following:

- ,an inert carrier and a surfactant, in which Z is cyano,

each R is selected from the group consisting of hydrogen, lower alkyl and lower alkenyl and R is selected from the group consisting of lower alkyl and lower alkenyl, said lower alkyl and lower alkenyl groups having up to about 6 carbon atoms.-

twenty-third Day of March 1976 9 [SEAL] A ttest:

RUTH-C. MASON C. MARSHALL DANN Altestmg Ofjrcer Commissioner uflarems and Trademarks 

1. THE METHOD FOR CONTROLLING WEED GROWTH WHCIH COMPRISES APPLYING TO THE LOCUS OF SAID WEEKS A PHYTOTOXIC AMOUNT OF A COMPOUND OF THE FORMULA
 2. The method in accordance with claim 1 in which said compound is applied at a rate of about 1 to 8 pounds per acre.
 3. The method in accordance with claim 1 in which said compound is N3,N3-diethyl-2,4-dinitro-6-cyano-1,3-phenylenediamine
 4. The method in accordance with claim 2 in which said weeds are grassy weeds.
 5. The method in accordance with claim 1 in which
 6. The method in accordance with claim 2 in which said compound is applied as a pre-emergence treatment.
 7. The method in accordance with claim 1 in which said compound is N3-(3-pentyl)-2,4-dinitro-6-cyano-1,3-phenylenediamine.
 8. A herbicidal composition comprising a phytotoxic amount of a compound of the formula 